Means for guiding weft threads

ABSTRACT

A weft raising member is mounted adjacent the advanced position of the hook of a latch needle reciprocated alongside one edge of a fabric being woven on a shuttleless loom. Each time a weft thread is inserted through a warp shed by a carrier from the opposite side of the fabric, the weft raising member operates to raise the inserted weft thread against its tension and hence to cause the hook of the latch needle to pass thereunder. The weft raising member is lowered immediately thereafter to permit the weft thread to become straight again and caught in the open hook of the latch needle, which needle will then form a loop of the weft thread to anchor the same.

United States Patent 1191 Nogai i 1 MEANS FOR GUIDING WEFT THREADS [75] Inventor:

[73] Assignee: Yoshida Kogyo Kabushiki Kaisha,

Tokyo, Japan [22] Filed: Dec. 21, 1972 [21] App]. No.: 317,172

Akira Nogai, Uozu, Japan 11/1966 Johnson 139/124A 1451 Sept. 30, 1975 Prinu11' E.\'aininerHenry S. Jaudon Atrurney, Agent, or FirmBucknam and Archer 5 7 1 ABSTRACT A weft raising member is mounted adjacent the advanced position of the hook of a latch needle reciprocated alongside one edge of a fabric being woven on a shuttleless loom. Each time a weft thread is inserted through a warp shed by a carrier from the opposite side of the fabric, the weft raising member operates to raise the inserted weft thread against its tension and hence to cause the hook of the latch needle to pass thereunder. The weft raising member is lowered immediately thereafter to permit the weft thread to become straight again and caught in the open hook of the latch needle, which needle will then form a loop of the weft thread to anchor the same.

1 Claim, 6 Drawing Figures US. Patent Sept. 30,1975 Shee tllof3 3,908,708-

US. Patent Sep t. 30,1975 Shee t 2 of3 3,908,708

US. Patent Se pt. 30,1975 SheetELc f3 3,908,708

. I MEANS FOR GUIDING WEFT THREADS BACKGROUND OF THE INVENTION This invention relates generally to looms and in particular to shuttleless looms such for example as needle looms in which a carrier is employed in lieu of the conventional shuttle for inserting a weft thread through a shed of warp threads to be beaten u p tothe fell ofa fabric being woven and also to be formed into a selvedge along one edge of the fabric. More specifically, the invention is directed to a method and means for guiding the inserted weft thread. I

In a known loom of this type, the weft thread carried through the warp shed from one side of the fabric being woven thereon is engaged by the open hook of a latch needle reciprocably mounted on the other side of the fabric. The engaged weft thread is then anchored by being drawn through the previously formed loop of the weft thread, and as this loop is subsequentlycast off over the closed hook of the latch needle a new loop is formed concurrently. This procedure is repeated to form a selvedge by the weft thread along the edgeof the fabric.

The above stated conventional arrangement required utmost precision regarding the operations and relative positions of the carrier and the latch needle, because the inserted weft thread mustbe caught by the hook of the latch needle at the exact moment when the carrier, moving substantially transversely of the fabric, and the latch needle, moving parallel to thefabric, arrive at their respective'predetermined positions. Pooradjustment of these members results in the failure of the latch needle to catch the weft thread. However, it is difficult to maintain the members in precisely adjusted condition during high speed operations which cause unavoidable vibrations of the entire machine. This accounts for the defective fabrics often produced during high speed performance of the conventional shuttleless looms.

SUMMARY OF THE INVENTION In view of the noted difficulties'of the prior art, it is an object of this invention to provide an improved method of guiding the weft threadwhich'has been inserted through a warp shed in a shuttle'less loom, in such a manner that the weft thread is caught smoothly and unfailingly by the hook of a latch needle, thereby making possible for the loom to operate properly at high speed. j i

lt is also an object of this invention to'provide simple means which can be easily built in a shuttleless loom of known construction for guiding 'the'weft thread in accordance with the method of the invention.

Briefly summarized, the improved method of this invention comprises the steps of applying an upward pressure to a weft thread inserted through a warpshed to raise the same against its'tensionata portion adjacent an advanced position of a hook of a latch needle, causing the hook of the latch needleto pass under the raised portion of the inserted weft thread, and releasing the upward pressure whereby the inserted weft thread is caught in the hook of the latch needle as the same becomes straight again owing to its own tension.

Based on this improved method, the invention further provides means for guiding the weft thread in accordance therewith, comprising a weft raising member supported adjacent an advanced position of a book of alatch needle, and drive means for moving the weft raising rnember up and down in timed relationship with the operations of the latch needle and a carrier adapted toinsert the weft thread through a warp shed.

By the provision of the weft raising member according to'the invention, no dipping or other vertical motion of the carrier or of the latch needle is required to ensure reliable catching of the weft thread by the hook of the lat'ch ne edle. Further by simple adjustment of the operation of the weft raising member, a weft thread of various sizes and materials can be used together with warp threads for weaving a fabric of any desired width. The features which are believed to be novel and characteristic of the invention are set forth with particularity in the appended claims. The invention itself, how ever, both as to its method and the means for carrying out the same, as wellas further objects and advantages thereof, will be best understood from the following description of a specific embodiment taken in conjunction with the accompanying drawings in which like reference characters denote like parts throughout the several views. I I u 4 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a fragmentary side elevational view explanatory of the construction of a dual needle loom incorporating theimproved means of the invention;

7 FIG. 2 is a framentary top plan view of the dual needle loomof FlGfl; FIG. .3 is a vertical sectional view showing drive means for a weft raising member in the dual needle loom of FIGS. 1 and 2; and V FIGS. .4A, 4B and 4C, respectively, illustrate the progressive steps of weft guiding operation according to the invention by a series of fragmentary top plan views in the left-hand row and a corresponding, series of side elevational .views in the right-hand row.

DESCRIPTION OF THE PREFERRED v EMBODIMENT The invention is hereinafter described more spe cifically as applied to a dual needle 100m of well known construction capable of simultaneously weaving twp strips of fabric such for example as tapes for use in slide fasteners. An example of the dual needle loom is,illustrated in FIGS. 1.and 2 in orderto make clearthe advantages and features ofv this invention. The exemplified loom includes a cooperative pair of carriers l0,

FIG-12yf0f inserting weft threads 1-1 into opensheds formed by dividing or.shedding, warp threads. 12 as shown in FIG. 1. On the sidesof woven fabrics 13 opposite the carriers 10, latch. needles l4are provided for torrning selvedges along the edges of the fabrics by anchoringthe successively inserted'weft threads, the latch needles having hooks at their leading ends which are opened'and closed by latches-in the usual manner. A reed 15, -having'two sets of comblike arrangement of dentsin side-by-side relationshipas in FIG. 2, recipro- "catesto beat the inserted weft'threads to the fells of both fabrics 13. Although not shown in the drawings, the dual needle loom further comprises, in accordance with conventional terminology, a shedding motion for dividing the warp threads as aforesaid, a let-off motion for delivering the warp threads at a regulated tension from a warp beam as the fabrics 13 are woven, and a take-up motion for rolling up the woven fabrics.

It may be noted that the constructions of the various means referred to in the preceding paragraph are all conventional and do not constitute a part of this inven tion. Their operations also take place substantially in accordance with the prior art. Each of the carriers 10, for example, is driven through a known linkage mechanism including four links 16, 17, 18 and 19 and an cecentric wheel 20 operatively combined together in such a manner that an eye 21 at the leading end of each car rier moves along the path indicated by the dot-anddash line in FIG. 2. Each of the latch needles 14, also driven through a known linkage mechanism, moves back and forth alongside one edge of each fabric 13 in the usual manner, with temporary stops at both extremities of its stroke. The reed 15 is swung as indicated by the double-headed arrow in FIG. 1 by an arm 22 on a crankshaft 23 driven by a belt 24 in a well timed manner.

The invention is characterized essentially by the provision of a weft raising member 25 which moves up and down at regulated time intervals in the adjacency of the advanced position of the hook of each latch needle 14. As best illustrated in FIG. 3, the weft raising members 25 in this embodiment of the invention are fixedly mounted on a rockshaft 26 extending horizontally through a machine frame 27 and are prevented from possible contact with the fabrics 13 by means of plates 28 secured between the weft raising members 25 and tables 29 on which the fabrics travel as they are woven. The rocksh'aft 26 is driven through three interconnected links 30, 31 and 32 by an input or drive shaft 33 which rotates in alternating directions at suitable time intervals, in such a manner that the upwardly bent free end of each weft raising member intermittently moves up and down in timed relationship with the operations of the various other mechanisms of the loom for guiding the respective weft threads 11 as hereinafter discussed with reference to FIG. 4.

When the reed 15 starts retracting to the right, as seen in FIG. 4A, after beating the previously inserted weft thread to the fell of the fabric 13, a new warp shed is formed as usual by the aforesaid shedding motion. Thereupon the earrier'10 having the weft thread 11 inserted through its eye 21 starts traveling through the newly formed warp shed, followed immediately by the advancement of the latch needle 14 toward the retracted reed 15, as indicated by the arrow in FIG. 4A. During this forward stroke the latch needle 14 has its latch 34 turned by a brush 35, FIG. 1, to open the hook 36 and moves through the previously formed loop 37 of the weft thread until the loop is wrapped around its shank portion. When the carrier 10, the latch needle 14 and the reed 15 have arrived at their respective positions of FIG. 4A, the weft raising member 25 starts moving in its upward stroke from below the plane of the fabric 13 in accordance with the novel concepts of this invention.

As the reed l completes its return stroke to the right as viewed in FIG. 4B, the latch needle 14 is held at a temporary standstill in a predetermined position whereas the carrier further travels through the warp shed to the opposite side of the fabric. However, immediately before the thus inserted weft thread 11 is carried above the open hook 36 of the latch needle 14, the

weft raising member 25 momves as above mentioned in its upward stroke to raise the weft thread at llu, as indicated in FIG. 4B, against its tension. The open hook of the latch needle is thus caused to pass under the raised portion 11a of the weft thread. As the weft raising member is subsequently rapidly lowered below the plane of the fabric 13, the weft thread becomes straight again due to its own tension and is now properly caught in the open hook of the latch needle, as indicated by the chain-dotted line in FIG. 4B.

Thereafter the carrier 10 continues traveling along its predetermined path depicted in FIG. 2, while the latch needle 14 and the reed 15 start moving back toward the fell of the fabric 13. When the carrier 10 and the latch needle 14 have reached their respective positions shown in FIG. 4C, thelatch 34 is'again turned by the brush 35 of FIG. 1 to close the hook 36 in which is caught the portion 11a of the weft thread. During further retraction of the latch needle 14 a loop of the weft thread portion is drawn through the old loop 37 and is thus properly anchored for selvedgc formation. The old loop is then cast off over the closed hook 37 of the latch needle. When the carrier 10 and the latch needle 14 have subsequently returned to their fully retracted or starting positions not shown in FIG. 4, the reed 15 beats the newly inserted weft thread 11 to the fell of the fabric 13.

By the repetition of the foregoing procedure the fabrics 13 are woven simultaneously without any of the difficulties listed earlier in this specification.

While the invention has been shown and described hereinbefore as embodied essentially in the weft raising member of specifically recited construction, it will be easyfor those skilled in the art to devise many modifications thereof without departing from the fair meaning or proper scope of the invention as defined by the appended claims. It is therefore to be clearly understood that all matter contained in the above description or shown in the accompanying drawings is of an illustrative and not a limitative nature.

What is claimed is:

I 1. In a shuttleless loom for weaving a fabric having a carrier for inserting a weft thread through a warp shed, a reed for bearing up said inserted weft and a reciprocable latch needle having a hook which is opened and closed by a latch for engaging the inserted weft thread and forming a loop in the weft, the improvement comprising a weft raising member pivotally supported adjacent an advanced position of said hook of said latch needle, and drive means for pivoting said weft raising member so that its weft engaging portion moves up and down in timed relationship with the operations of said carrier and said latch needle whereby said weft raising member is pivoted upward to raise the inserted weft thread against its tension at a point adjacent the advanced position of said hook of said latch needle and hence to cause said hook of said latch needle to pass under the raised portion of the inserted weft thread, said weft raising member being then pivoted downwardly rapidly to cause the inserted weft thread to be caught in said hook of said latch needle as the same becomes straight again owing to its own tension. 

1. In a shuttleless loom for weaving a fabric having a carrier for inserting a weft thread through a warp shed, a reed for bearing up said inserted weft and a reciprocable latch needle having a hook which is opened and closed by a latch for engaging the inserted weft thread and forming a loop in the weft, the improvement comprising a weft raising member pivotally supported adjacent an advanced position of said hook of said latch needle, and drive means for pivoting said weft raising member so that its weft engaging portion moves up and down in timed relationship with the operations of said carrier and said latch needle whereby said weft raising member is pivoted upward to raise the inserted weft thread against its tension at a point adjacent the advanced position of said hook of said latch needle and hence to cause said hook of said latch needle to pass under the raised portion of the inserted weft thread, said weft raising member being then pivoted downwardly rapidly to cause the inserted weft thread to be caught in said hook of said latch needle as the same becomes straight again owing to its own tension. 